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Endogenously generated sulfur dioxide and its vasorelaxant effect in rats
Shu-xu Du1, Hong-fang Jin, Ding-fang Bu
1Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Acta Pharmacologica Sinica
|July 31, 2008
Summary
Endogenous sulfur dioxide (SO2) and aspartate aminotransferase in rat aorta exhibit vasorelaxant effects. SO2 likely inhibits L-type calcium channels, contributing to vascular smooth muscle relaxation.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Pharmacology
Background:
- Sulfur dioxide (SO2) is an endogenous gasotransmitter with emerging roles in cardiovascular regulation.
- The SO2/aspartate aminotransferase pathway's specific contribution to vascular tone is not fully elucidated.
Purpose of the Study:
- To investigate the endogenous production and localization of the SO2/aspartate aminotransferase pathway in rat vascular tissues.
- To assess the vasorelaxant effect of SO2 on isolated rat aortic rings and explore underlying mechanisms.
Main Methods:
- Quantification of SO2 content using high-performance liquid chromatography with fluorescence detection.
- Measurement of aspartate aminotransferase activity and gene expression (RT-PCR).
- In situ hybridization for mRNA localization; in vitro assessment of vasorelaxation in aortic rings using calcium channel modulators.
Main Results:
- Aorta demonstrated the highest SO2 content among tested vascular tissues.
- Aspartate aminotransferase mRNA was localized to endothelial and smooth muscle cells in the aorta.
- SO2 derivatives induced concentration-dependent relaxation of aortic rings, with complete inhibition of the response by nicardipine.
Conclusions:
- Endogenous SO2 and its derivatives possess significant vasorelaxant properties in rat aorta.
- The vasorelaxant mechanism of SO2 appears to involve the modulation or inhibition of L-type calcium channels.
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